My Wife is a Demon Queen Wiki

“Is the one that’s chosen to save this world this weak? It looks like I’ll still have to teach you a lot, this way, you’ll truly become the king of this kingdom.”

-Isabella to Xiang Ye


Isabella Osa is the former queen of the the Demon Tribe and the titular deuteragonist of My Wife is a Demon Queen. After being betrayed by her High Commander Lilian, Isabella fulfills an ancient prophecy by summoning an ordinary human named Xiang Ye to aid her in reclaiming her throne. Having lost her demonic powers, Isabella is currently hiding amongst the humans while learning swordsmanship and magic at the Royal Academy as Xiang Ye’s wife, Yi Bei.


Isabella is solemn and dignified, as befitting a queen. However, she does care for the welfare of her followers, and does get upset if they suffer. Although she respects power, she is not cruel and does not believe in mindless war. At the beginning of the story, she disdains the human race, and is very harsh towards Xiang Ye. As the story progresses, she begins to trust and protect Xiang Ye, although she still remains cold. There are a few occasions when Isabella switches to a different personality which is harsher, more cruel and very proud of her status as the queen. Both personalities begin to merge because of Isabella's growing attraction towards Xiang Ye.

  • Fear: Losing her loyal followers.
  • Hobbies: Bathing.


She is an attractive young lady, with long white hair and red eyes. When she is in her demon form she has pointed ears and purple horns as well as a long tail. When she is a human, she lacks all her demonic attributes, and is beautiful enough to attract many young men.


Xiang Ye: Upon their first meeting, Isabella is disappointed with Xiang Ye's apparent lack of power, but is compelled to elope with him to escape from Tols Angus. She is further irritated when she is forced to live in the Human Tribe as Xiang Ye's wife, Yi Bei. Yi Bei pushes away Xiang Ye in an attempt to protect him from further danger but decides to trust him when he promises to be with her. Behind her cold demeanour, she is faithful, caring, and protective of Xiang Ye, being happy for his achievements and getting slightly jealous at the attention he receives from people. After being heavily injured from the fight with Balien, Yi Bei's personality switches to a more demonic version, and takes sadistic satisfaction in commanding Xiang Ye, calling him her servant. Gradually, this personality becomes genuinely attracted to Xiang Ye and begins to accept him as her husband.

Humanity: Contrary to her declaration that humans are all trash, she does indeed want peaceful coexistence, but is fond of contests of strength and skill.

Tols Buri: The eldest son of the Regent, Tols Angus. Tols Buri makes lustful advances towards Isabella who despises him. During their tournament duel, Buri crassly offers to make Isabella his mistress, to which she responds by hacking his arm. Since then, Buri despises her.

Rennes: The eldest prince of the Human Royal Family and the most gifted student of the magic class that Isabella attends. Isabella views Rennes as a worthy opponent, indifferent of Rennes's attraction towards her. Despite being aware that Isabella is Xiang Ye's wife, Rennes makes advances towards her, although she ignores them. During the tournament, Rennes presumptuously challenges Xiang Ye to a death match in an attempt to kill him and possess Isabella. Isabella is prepared to leap into the arena and save Xiang Ye from Rennes, however Xiang Ye is able to free himself and defeat Rennes on his own.



At the beginning of the story, she lost much of her magical power because of her betrayal. She summoned Xiang Ye with the intent of receiving help only to be disappointed with the end result. Not only was she disappointed that he had no magical power she was also angry that he was a human, the race of her sworn enemy. as she lost the rest of her demonic power she ended up reverting to a form that resembled a human rather than a demon. Her and Xiang Ye attempted to escape the human armies only to be intercepted by Sophisas and his White Dragon Knights. They both decided to pose as former slaves of the demon tribe, because of this ruse they were able to receive lodging from the rich captain.

The Royal Academy[]

Isabella sparring with Buri

Refusing to stay in the rich captain's care for much longer she decides that she along with her husband should join the Royal Academy. Once there all the teachers take note of her extreme talents with the sword and magic. She is torn between the two as the teachers Dorona and Wadley Aisi bicker over whose class she would be better suited. Eventually, she decides that taking both classes would be the best path for her and battles with Tols Buri who she bests in basic combat though he uses his boundary force against her in an illegal move. Rennes steps in to stop the attack and carries her to safety (to her frustration). Dorona ends the battle and scolds her opponent, though she is pleased and impressed by Isabella's amazing fighting potential and future promise in the academy.

Battle for the Forging Stones[]

She helped her husband in securing the forging stones by using her skills in battle. The operation was a success and they were able to secure the stones.


Upon hearing about the Kingdom Cup Tournament, Isabella thought of this as an opportunity to leave the walls of the human clan's city and get back to the demon clan. Since the winner would receive the rank of Major in the military and have the ability to come in and out of the city as they pleased.

First Round[]

Isabella with baby Queen of Thorns

  1. The first round of the tournament was a race with the goal of getting tokens to progress to the battles in the second round. She and others were teleported to a beach and had to cross a large body of water as quickly as possible. While others used magic and means like swimming Xiang Ye created a boat and sped through the large body of water.
  2. The second part of the competition required them to make it through a burning forest. Here The Queen of Thorns fought them angered by the humans burning her forest. She proved to be a difficult opponent since she could not be killed within the forest. However, it was later discovered that she was once Isabella's pet when they were both children.
  3. The final part of the first round was navigating a mountain with heavy winds. Xiang ye and his friends fought rock Golems and the refinery class when they reached the top of the mountain. While Xiang Ye was injured he was able to move onto the next round thanks to Isabella's help who carried him through the portal along with his token's. She went on to the next round to battle with the hopes of winning.

Second Round[]

Before her first match, she is given a sword made from useless lumber as a gift from Xiang Ye. She accepts but tells him he is becoming cocky and thinking too highly of himself.

First Kiss

  1. During her first battle, she fights Buri once again. As she gets the upper hand he transforms into his [dragon] form in a hope to overpower her. However, he becomes cocky and doesn't realize the young [demon] queens true potential. She releases some of her powers on him and cuts his arm clean off. She wins the battle fairly easily. This angers Buri's younger brother Buno who attempts to attack her, only to be foiled by Penny.
  2. During her second battle, she is placed against Tols Penny who proves to be a more powerful adversary for Isabella. This tough battle causes her to lose control of her demon powers and run amok. While the Principle is able to conceal her identity by blocking the sight of the audience she continued to relentlessly attack Penny. Hoping to stop her Xiang Ye kisses her with the hope it would quell her demon side. This works but both she and Penny are taken out of the tournament ending her chances of winning the competition.


  1. She roots for Xiang ye in the finals and tells him that he better not lose.

Powers & Abilities[]

Boundary Force: According to Isabella, she has a unique demon core due to being born in the [Osa] bloodline. It is capable of generating immense boundary force and it can rival the combined strength of members of the human royalty who possess formidable Dragon-forms. When she manifests her "evil" Boundary Force, she does this. She's still a good and honorable individual who is loved by her people. Fully unleashing her Boundary Force can easily reveal that she's from the Demon tribe, which is a bad thing in human territory.

Evil: Her most powerful magic is "darkness" based, her Demon Queen "aura" is black and called "evil" on a repeated basis, but she, personally, is a good and kind woman who deserves the loyalty of her followers.

Swordsmanship: Isabella had practiced swordplay under [Mochia] and is currently learning under [Dorona]. She wields the Useless Lumber sword Xiang Ye had crafted for her.

Magic-Swordsmanship: In Royal Academy, she takes the magic and sword classes simultaneously and later combines spells with sword moves.


  • Black Sword/Useless Lumber sword: The useless lumber sword Xiang Ye makes for her is a fearsome weapon that owes its black color to its source material. She herself admits it is a "decent weapon".
  • Magic Core Armor: An electromechanical armor designed for her by Xiang Ye.
  • II Armor: A variant. Isabella's second Powered Armor shows off more skin. Apparently, she wanted a more agile suit.
  • Necklace: The necklace Dorona gave her to control her Demon boundary force absorbs it when she tries to unleash it against [Balien]. In Chapter 212, after Xiang Ye destroys the pendant Dorona gave her so her boundary force can help her recover, the alternate persona grabs Xiang Ye by the throat and then goes full-tilt fem-dom as showcased in chapter 1's In Medias Res.


  • Her alias "Yi Bei," given to her by Xiang Ye comes from the Chinese pronunciation of Isabella: Yī shā bèi lā.
  • Very mild, but she doesn't like it when Xiang Ye interacts with other attractive women.
  • Her Demon Queen persona has a visible little fang.
  • She's the first student to both consider and be permitted to study both swordsmanship and magic simultaneously.
  • Her Super-Powered Evil Side is a manifestation of all her suppressed desires.
  • She is horrible at cooking.
  • Isabella does not know the true reason why Lilian betrayed her, but Xiang Ye knows and chose to keep it a secret from her for the time being.